On Tuesday, Jumppanen and a handful of Gardner staffers and supporters watched as workers wheeled in a brand-new Steinway concert grand Model D. This wasn’t just another ­piano. The instrument, built overseas by dozens of workers by hand and selected by Jumppanen during a scouting trip to Hamburg, replaces the 27-year-old piano that was used in the Gardner’s former performance space, the Tapestry Room. The new Steinway is in line with models used in the world’s elite symphony halls. Longtime Gardner supporter Brit d’Arbeloff picked up its $184,000 cost, helping the museum take another step in securing a role as one of the city’s leading venues for classical music.

Earlier this summer, Jumppanen, a regular performer at the Gardner who often consults on musical matters, traveled to Steinway’s factory in Hamburg to select the piano. He was at the museum to show it off when it arrived.

“Can’t wait to hear you play it, Paavali,” said Gardner’s director, Anne Hawley.

“Here we go, history is being made now,” said Scott Nickrenz, the Gardner’s music director, cueing Jumppanen and flutist Paula Robison to play part of a piece by Pierre Boulez.

The Gardner should give credit to a particularly slow parking valet in helping lead to the piano purchase.

They had good reason to be excited.

“You don’t just order these pianos,” said Paul Murphy, owner of the local Steinway dealer M. Steinert & Sons. “Because it’s handcrafted, it takes 12 or 13 months to make one.”

Typically, an orchestra swaps a Steinway every decade. The Gardner, with a more limited budget and a focus on the ­visual arts, has had to get more wear out of its Steinways. The most recent, purchased in 1985, has been sold for an undisclosed sum to the Yellow Barn Music School and Festival in Vermont.

This year would have been a particularly difficult time for the museum to buy a new one, said Hawley. The Gardner’s new building opened in January and the museum is still $26.5 million short of the $180 million being raised for construction costs, the renovation of the existing building, and endowment.

The Gardner should give credit to a particularly slow parking valet in helping lead to the piano purchase. That night in January, after Denk had performed, d’Arbeloff found herself near the museum’s front door, waiting for her car.

There she ran into Jumppanen and they began chatting. The pianist knows d’Arbeloff through the regular games of bridge she plays with a group that includes Nickrenz, a neighbor in Brookline.

During the conversation, Jumppanen mentioned Denk’s comments about the piano. The next day, d’Arbeloff talked with Nickrenz, ostensibly to schedule their next bridge night.

“And she says, ‘I understand you need a new piano,’ ” recalled Nickrenz. “And I said, ‘Do you want to buy one?’ ”

“So aggressive,” said Hawley.

“Blunt is the word you’re looking for,” said Nickrenz.

In fact, the idea made perfect sense to d’Arbeloff. Her husband, Alex d’Arbeloff, who cofounded Teradyne, had been a trustee at the Gardner and a member of the museum’s building committee. He died in 2008; the piano would be named after him.

But first, the Gardner had to select a Steinway.

Jumppanen headed to Hamburg on June 16 with a Finnish piano technician, Matti Kyllonen. They looked at seven Steinway concert grands, all of which had been through a production process that included creating an outer shell by gluing and pressing together more than a dozen sheets of maple wood, building a sound board from spruce, and, finally, a two-day testing process during which all 88 keys were struck continuously by a machine.

The pianos were all Model D’s, but didn’t sound the same, said Jumppanen. He played single notes, a few passages — some sections loudly, some quietly. He quickly settled on two potential choices.

“Because they’re handmade with wood, they all sound just a little bit different,” he said. “The other one felt a little more even. A little more limited compared to this one. Though if that piano were here, I think the reaction would have been similar.”

The Steinway that the Gardner sold, Jumppanen said, was simply past its prime. He was loath to criticize it too harshly, both because it’s going to Yellow Barn and also because it is still a good piano.

“It’s a beautiful piano and I think as time goes by it needs to move to a little bit smaller venue,” he said. “If you have a modern hall like this hall, you feel you need to have a modern piano. It’s the sound. The sound gets a little bit softer [as a piano ages], a little bit more lyrical. It’s not as versatile, not as strong. It’s a little like athletes.

“Pianos are at their best between two and 10 years. Somehow, when the old piano was brought into the new hall, a number of people figured out it’s time to get a new one.”

Tuesday morning, Nickrenz, in a nod to museum founder Isabella Stewart Gardner, brought doughnuts and champagne to celebrate the piano’s arrival. (She did the same upon the museum’s opening, in 1903.)

He picked a very specific piece to usher in the new Steinway: the first section of contemporary composer Boulez’s “Sonatine,” for flute and piano.

“I don’t want people monkeying around,” he said. “I wanted a statement, and the statement is going to be Pierre Boulez. With everything we’re doing at the museum, the strength and power of that piece is better than some nice, romantic piece.”

Jumppanen, wearing loafers and no socks, began the piece with Robison. The tiny audience, made up of Nickrenz, Hawley, d’Arbeloff, and two Gardner interns, applauded four minutes later, when they stopped.

“Hey, play some Chopin,” shouted Nickrenz.

“How about a Bach Fugue?” added Hawley.

First, Jumppanen
commented on the piano.

“Have you ever heard a piano play so clearly here” — he played low notes — “and here?” as he then played high notes.

Nickrenz suggested “Moonlight Sonata.”

“Suddenly, I’m a jukebox,” said Jumppanen, laughing.

After he finished playing, Nickrenz stood and looked over at d’Arbeloff, who was smiling.